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Lenovo ThinkPad T420 with UEFI Only


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I did a fresh install tonight, and all is well. I did find the newer zip you posted and used that for the last 2 attempts (the non-fresh and fresh.)

Before the fresh install while I was having the no-display issue, I did try the brightness keys. They would indeed adjust the brightness of the back light, but the screen was still displaying black. This was using the Fn+Home/End. I saw the Pause key mentioned somewhere and pressed that as well. Is Pause/SrLck a different brightness control? I also had tried the external DP displays on both the laptop and dock, but one thing I did not try was the VGA outputs.

But it's all good; I realized after poking around in Terminal for a bit that I had already backed stuff up to the secondary HDD in the laptop back when I first upgraded to High Sierra and thus didn't really have anything on the main drive to back up. I just wiped it clean and it was no big deal, just have to reinstall a few things. It would have been nice to figure out what the issue was in case it happens again, and future OS upgrades are still going to be scary on this thing, but I'll deal with them when the time comes.

I was also previously experiencing the occasional lock ups on both the T420 and T520, so it's good to hear that this has went away? Other than that, the only issues I have with them is with the occasional lines and artifacts in app windows, which I understand can be caused by low quality RAM? I'll have to swap a few sticks around and see what happens.

Thanks for the help and advice, not to mention the great guide for these machines!

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So far so good. The blank screen thing did come back on one boot, but on the next reboot it was fine.

I've also had lockups yesterday and today. Both involved Safari, when clicking either the URL box or the tabs. There were times in the past where lockups were always while using Safari. Does anyone else have issues like this- lockups only when using Safari?

It kind of sucks- while I'm normally a big fan of the newer Firefox, Safari is zippy as hell when it comes to web apps I use for work. I'm going back to Firefox and see if I can make it through a work day without a lockup.

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@vusun123 - no idea why there isn't a recent build on SF? I just build my own package of course! how's things with you!? 

@copperspeed -  is your headphone stuck? i would perhaps put a headphone in and out a few times? I don't have low volume problem with my T420. what is your system - please create a profile in your signature.

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Hi guys, using this guide and files for a while now in Sierra, all good , thank you very much!

However, I need to upgrade to High Sierra now (iPhone updated to 10.3 -> latest xcode version in Sierra can't work with that etc -> Need High Sierra and a newer xcode version).

I used AppStore to download High Siera. It did start the process of updating, but when I get to the part to select the HDD where to install it doesn't want to accept the HDD macOS I am using (Saying the it's missing the firmware partition).

I tried to follow the 2.3 steps from the guide to no avail. 

Also I don't understand the meaning of

"

  1. Manually mount and install of the ESP bits to disk0 by following the same procedure as for the USB.

"

Other that I tried everything I could think of. 

Thanks in advance!

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On 26/02/2018 at 11:18 PM, jus12 said:

Hi, I need your help.

yesterday I had to reinstall High Sierra on my T420. All is working fine with the latest Clover.zip package. But after wake from sleep my power led and sleep led on the cover keeps flashing.

Everything else works fine after sleep. I need to reboot, of course, for both leds to stop flashing.

 

Do you have ideal what can cause that? I have disabled hibernation and removed sleep image (hibernate mode set to 0).

OK I think I found the problem. For many years I had installed external disk in CD Bay instead of CD Drive. When I put CD Drive back, or just remove the external drive from CD Bay, led behaves as it should. So something is not right with the external drive sitting in the cd bay, then.

OK I think I found the problem. For many years I had installed external disk in CD Bay instead of CD Drive. When I put CD Drive back, or just remove the external drive from CD Bay, led behaves as it should. So something is not right with the external drive sitting in the cd bay, then.

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On 4/13/2018 at 8:35 PM, jus12 said:

OK I think I found the problem. For many years I had installed external disk in CD Bay instead of CD Drive. When I put CD Drive back, or just remove the external drive from CD Bay, led behaves as it should. So something is not right with the external drive sitting in the cd bay, then.

Hmm, I also have a HDD in my CD bay, maybe that is my problem. Oh and it's a m2 SSD in an adapter  that is in the CD bay and my macOS boots from it. I guess I should try switching the drive to the main bay.

Another strange thing is that I got a downloaded version of the installer (macOS 10.13.1) to try. And it does see the hard drive and starts the installation process, but when it restarts I choose the macOS install from the menu (Clover?) and after the Apple logo with the loading bar finishes loading, I get a the Prohibitory Symbol....

Hopefully this information will give more insights for the person who is willing to help.
Thanks!

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Does anyone else get the occasional line flickering on the display? Also, has anyone else got a problem with the laptop not going into sleep when the lid is closed? I suspect that Mail is misbehaving, as it also prevents shutdown until forced to quit. 

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8 hours ago, bedfellow said:

Does anyone else get the occasional line flickering on the display? Also, has anyone else got a problem with the laptop not going into sleep when the lid is closed? I suspect that Mail is misbehaving, as it also prevents shutdown until forced to quit. 

 

I get the line flickering and random lines and artifacts through windows that are open sometimes. I've read that it can be from poor quality RAM. I'm not sure what constitutes good vs. poor quality; I've tried switching RAM around between a few different brands, making sure to use the same kind of stick in both slots, but it didn't help. The same RAM works fine in Windows.

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8 hours ago, Mezmaron said:

 

I get the line flickering and random lines and artifacts through windows that are open sometimes. I've read that it can be from poor quality RAM. I'm not sure what constitutes good vs. poor quality; I've tried switching RAM around between a few different brands, making sure to use the same kind of stick in both slots, but it didn't help. The same RAM works fine in Windows.

I find that it's predominantly in videos, including those on Facebook. Often consisting of one band but occasionally two running across the video. It does however also manifest in some other applications. I'm not sure if it's a RAM issue, appears to be more of a driver issue to me.

Edited by bedfellow
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  • 2 weeks later...

Hi all,

 

1.Is there an option to create bootable flash without using mac computer?

2.If i do not need wifi connection do i need to use modded bios?

3.What is the preffered bios version that  I can use on my laptop since for t420 I see version  from 1.46 and above but what about W520?

 

Thank you all for your great help and all information written here.

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  • 3 weeks later...

10.13.5 and sound works for me? I will push a new zip out when i get home later today. 

The latest zip contains a cleaned-up/fixed AppleALC.kext. 

Edited by tluck
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